The internet tells me it's from the Tiagra product line, but all I can see on the part itself is the engraved part number FD-4603.

Its clamp will fit a 31.8mm tube, but could probably be shimmed to fit a smaller tube diameter. 

The actuating lever looks like it will only be compatible with bottom-pull cables.

The item is in good cosmetic condition considering it has seen about three years of use, and it is in full working order. 

The part came off my last bike while I was doing some upgrades and kept 'just in case', but that was a couple of years ago now so I don't see myself needing it anytime soon.